Radio communication system, terminal device, base station device, radio communication method, and integrated circuit with efficient transmission and reception through repetition

ABSTRACT

Disclosed is a radio communication system in which a base station device and a terminal device communicate with each other, and the terminal device performs a random access procedure. The base station device notifies the terminal device of random access common configuration information including the number of repetitions for each level, information indicating a relationship between group information of random access preambles and the level, and the number of attempts of preamble transmission for each level. A MAC layer in the terminal device performs processing of increasing the level in a case that a first counter exceeds the number of attempts of transmission corresponding to the level.

TECHNICAL FIELD

The present invention relates to a radio communication system, aterminal device, and a base station device, and more specificallyrelates to a technology for a radio communication system, a base stationdevice, a terminal device, a radio communication method, and anintegrated circuit which are directed to machine type communication ormachine to machine communication.

This application claims priority based on JP 2015-076398 filed on Apr.3, 2015, the contents of which are incorporated herein by reference.

BACKGROUND ART

In the 3rd Generation Partnership Project (3GPP), a W-CDMA scheme hasbeen standardized as a third generation cellular mobile communicationscheme to provide a service. HSDPA with a higher communication speed hasbeen also standardized to provide a service.

On the other hand, in 3GPP, the advance of the third generation radioaccess (Long Term Evolution (LTE) or Evolved Universal Terrestrial RadioAccess (EUTRA)) has been also standardized to start a LTE service. As adownlink communication scheme in LTE, used is the orthogonal frequencydivision multiplexing (OFDM) scheme resistant to a multipathinterference and suitable for a high-speed transmission. As an uplinkcommunication scheme, taking into account a cost and power consumptionof a mobile station device, discrete Fourier transform (DFT)-spread OFDMscheme for a single carrier-frequency division multiple access (SC-FDMA)is employed which can reduce a peak to average power ratio (PAPR) of atransmit signal.

In 3GPP, LTE-Advanced (or advanced-EUTRA) that is further advanced fromLTE has also been continuously studied. In LTE-Advanced, it is assumedthat a band having the maximum bandwidth of 100 MHz is used in each ofan uplink and a downlink to perform communication at a transmission rateof 1 Gbps or greater in the downlink and 500 Mbps or greater in theuplink at a maximum.

In LTE-Advanced, it has been considered that multiple bands compatiblewith LTE are aggregated such that a mobile station device of LTE can bealso accommodated to attain the maximum band of 100 MHz. InLTE-Advanced, one band of 20 MHz or less in LTE is referred to as acomponent carrier (CC). The component carrier is also referred to as acell. Aggregating of the bands of 20 MHz or less is referred to ascarrier aggregation (CA) (NPL 1).

On the other hand, in LTE-Advanced, cost reduction has been studied fora mobile station device supporting a specific category such as machinetype communication (MTC) or machine to machine communication (M2M) (NPL2). Hereinafter, an MTC/M2M mobile station device or an MTC/M2Mcommunication device is also referred to as a machine type communicationuser equipment (MTCUE).

In order to attain a low-cost MTCUE complying with the LTE standard andthe LTE-Advanced standard, there has been proposed a cost reductionmethod including narrowing a transmission and reception bandwidth,reduction in the number of antenna ports/the number of RF chains,reduction in a transmitted and received data transfer rate, employmentof a half-duplex frequency division duplex mode, reduction in transmitand receive power, and extension of a discontinuous reception interval.In addition, there has also been suggested that reduction of maximumbandwidth is effective in a transmission and reception RF circuit andtransmission and reception baseband circuit of the MTCUE as a method inorder to attain a low-cost MTCUE.

In the MTC, coverage enhancement has been studied for enhancing atransmission and reception coverage of the MTCUE, in addition to thestudy for the cost reduction. In order to enhance the coverage, it hasbeen considered that a base station device repeatedly transmits downlinkdata or downlink signals to the MTCUE, and the MTCUE repeatedlytransmits uplink data or uplink signals to the base station device (NPL3).

For example, the base station device repeatedly transmits a physicalbroadcast channel (PBCH) to the MTCUE multiple times within 40 ms. In arandom access procedure, the MTCUE repeatedly transmits the same randomaccess preamble using multiple physical random access channels (PRACHs).The base station device having received the random access preamblerepeatedly transmits a random access response message. The base stationdevice notifies the MTCUEs in a cell using a broadcast channel (BCH) orindividually notifies each MTCUE of the number of repetitions (NPL 3).

For example, the number of repetitive transmissions of the random accesspreamble or the number of repetitive transmissions of the random accessresponse message is notified using the broadcast channel (BCH). It hasalso been studied that the number of repetitive transmissions of therandom access preamble includes multiple kinds of the numbers ofrepetitive transmissions such that the MTCUE can select one number ofrepetitive transmissions from the multiple kinds of the numbers ofrepetitive transmissions.

CITATION LIST Non Patent Literature

NPL 1: 3GPP TS (Technical Specification) 36.300, V11.5.0 (2013-03),Evolved Universal Terrestrial Radio Access (E-UTRA) and EvolvedUniversal Terrestrial Radio Access Network (E-UTRAN), Overalldescription Stage 2.

NPL 2: 3GPP TR (Technical Report) 36.888, V12.0.0(2013-06), Study onprovision of low-cost Machine-Type Communications (MTC) User Equipments(UEs) based on LTE (release 12).

NPL 3: “Rel-12 agreements for MTC”, R1-143784, 3GPP TSG-RAN WG1 Meeting#78bis Ljubljana, Slovenia, 6th-10th October 20144.

SUMMARY OF INVENTION Technical Problem

However, transmission control through repetition (or reception controlthrough repetition) is needed to be correctly managed between a terminaldevice and a base station device. For example, upon an occurrence of amismatch between the number of repetitions in a terminal device and thenumber of repetitions in a base station device, either of the devicesmay not receive in some cases.

The present invention relates to a radio communication system, a basestation device, a terminal device, a radio communication method, and anintegrated circuit for the terminal device and the base station deviceto efficiently perform transmission and reception through repetition.

Solution to Problem

(1) A radio communication system according to an aspect of the presentinvention is a radio communication system in which a base station deviceand a terminal device are configured to communicate with each other and,the terminal device is configured to perform a random access procedure,the base station device being configured to notify the terminal deviceof random access common configuration information including the numberof repetitions for each level, information indicating a relationshipbetween group information of random access preambles and the level, andthe number of attempts of preamble transmission for each level, and aMAC layer in the terminal device being configured to perform processingof increasing the level in a case that a first counter exceeds thenumber of attempts of transmission corresponding to the level.

(2) A terminal device according to an aspect of the present invention isa terminal device configured to communicate with a base station deviceand perform a random access procedure, the terminal device beingconfigured to, receive, from the base station device, random accesscommon configuration information including the number of repetitions foreach level, information indicating a relationship between groupinformation of random access preambles and the level, and the number ofattempts of preamble transmission for each level, and a MAC layer in theterminal device being configured to increase the level in a case that afirst counter exceeds the number of attempts of transmissioncorresponding to the level.

(3) A base station device according to an aspect of the presentinvention is a base station device configured to communicate with aterminal device, the base station device being configured to notify theterminal device of random access common configuration informationincluding the number of repetitions for each level, informationindicating a relationship between group information of random accesspreambles and the level, and the number of attempts of preambletransmission for each level, and assume that the level for the terminaldevice varies depending on the number of attempts of transmissioncorresponding to the level, and a success or failure in receiving arandom access response by the terminal device.

(4) A radio communication method according to an aspect of the presentinvention is a radio communication method applied to a terminal device,the terminal device being configured to communicate with a base stationdevice and perform a random access procedure, the radio communicationmethod including the steps of receiving, from the base station device,random access common configuration information including the number ofrepetitions for each level, information indicating a relationshipbetween group information of random access preambles and the level, andthe number of attempts of preamble transmission for each level, andincreasing the level by a MAC layer in the terminal device in a casethat a first counter exceeds the number of attempts of transmissioncorresponding to the level.

(5) A radio communication method according to an aspect of the presentinvention is a radio communication method applied to a base stationdevice configured to communicate with a terminal device, the radiocommunication method further including, at the base station device,notifying, the terminal device of random access common configurationinformation including the number of repetitions for each level,information indicating a relationship between group information ofrandom access preambles and the level, and the number of attempts ofpreamble transmission for each level, and assuming that the level forthe terminal device varies depending on the number of attempts oftransmission corresponding to the level, and a success or failure inreceiving a random access response by the terminal device.

(6) A integrated circuit according to an aspect of the present inventionis an integrated circuit applied to a terminal device configured tocommunicate with a base station device and perform a random accessprocedure, the integrated circuit including a first unit configured toreceive, from the base station device, random access commonconfiguration information including the number of repetitions for eachlevel, information indicating a relationship between group informationof random access preambles and the level, and the number of attempts ofpreamble transmission for each level, and a second unit configured toincrease the level in a case that a first counter exceeds the number ofattempts of transmission corresponding to the level.

Advantageous Effects of Invention

According to some aspects of the present invention, it is possible tocause a terminal device to perform a random access procedure usingefficient repetitive transmission and reception control. Moreover, abase station device can perform efficient data scheduling for a terminaldevice.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a diagram illustrating an example of a configuration of anMTCUE according to an embodiment of the present invention.

FIG. 2 is a diagram illustrating an example of a configuration of a basestation device according to an embodiment of the present invention.

FIG. 3 is a diagram illustrating an example of a random access groupaccording to an embodiment of the present invention.

FIG. 4 is a diagram illustrating an example of random access resourceselection processing for a random access preamble transmission accordingto an embodiment of the present invention.

FIG. 5 is a diagram illustrating an example of processing on a randomaccess response message according to an embodiment of the presentinvention.

FIG. 6 is a diagram illustrating an example of processing on aPDSCH/PUSCH repetition level command according to an embodiment of thepresent invention.

FIG. 7 is a diagram illustrating a physical channel configurationexample in LTE.

FIG. 8 is a diagram illustrating a downlink channel configurationexample in LTE.

FIG. 9 is a diagram illustrating an uplink channel configuration examplein LTE.

FIG. 10 is a diagram illustrating a configuration example of acommunication protocol concerning control information on a base stationdevice and a mobile station device.

FIG. 11 is a diagram illustrating a configuration example of acommunication protocol concerning user information on a base stationdevice and a mobile station device.

FIG. 12 is a diagram illustrating a contention based random accessprocedure.

FIG. 13 is a diagram illustrating a non-contention based random accessprocedure.

DESCRIPTION OF EMBODIMENTS

An OFDM scheme is employed for a downlink in LTE. A single carriercommunication scheme using a DFT-spread OFDM scheme is employed for anuplink in LTE.

FIG. 7 is a diagram illustrating a physical channel configuration inLTE. Downlink physical channels are consisted of a physical downlinkshared channel (PDSCH), a physical downlink control channel (PDCCH), anda physical broadcast channel (PBCH). Other than such downlink physicalchannels, a downlink synchronization signal and a downlink referencesignal are used as physical signals (NPL 1).

Uplink physical channels are consisted of a physical random accesschannel (PRACH), a physical uplink shared channel (PUSCH), and aphysical uplink control channel (PUCCH). Other than such uplink physicalchannels, an uplink reference signal is used as a physical signal. Theuplink reference signal includes a demodulation reference signal (DRS)and a sounding reference signal (SRS). The sounding reference signalincludes, more specifically, a periodic sounding reference signal(periodic SRS) and an aperiodic sounding reference signal (aperiodicSRS). Hereinafter, the sounding reference signal refers to the periodicsounding reference signal unless otherwise specified (NPL 1).

FIG. 8 is a diagram illustrating a downlink channel configuration inLTE. Each of downlink channels illustrated in FIG. 8 is consisted oflogical channels, transport channels, and physical channels. The logicalchannels define a type of data transmission service in which data istransmitted and received in a medium access control (MAC) layer. Thetransport channels define what characteristics the data transmitted viaa radio interface has and how the data is transmitted. The physicalchannels are physical channels carrying the data which is transported toa physical layer via the transport channels.

The downlink logical channels include a broadcast control channel(BCCH), a paging control channel (PCCH), a common control channel(CCCH), a dedicated control channel (DCCH), and a dedicated trafficchannel (DTCH).

The downlink transport channels include a broadcast channel (BCH), apaging channel (PCH), and a downlink shared channel (DL-SCH).

The downlink physical channels include a physical broadcast channel(PBCH), a physical downlink control channel (PDCCH), and a physicaldownlink shared channel (PDSCH). These channels are transmitted andreceived between a base station device and a mobile station.

Next, the logical channels are described. The broadcast control channel(BCCH) is a downlink channel used to broadcast system information. Thepaging control channel (PCCH), which is a downlink channel used totransmit paging information, is used when a network does not know a celllocation of the mobile station device. The common control channel(CCCH), which is a channel used to transmit control information betweenthe mobile station device and the network, is used by a mobile stationdevice not having a radio resource control (RRC) connection with thenetwork.

The dedicated control channel (DCCH), which is a point-to-pointbidirectional channel, is used to transmit individual controlinformation between the mobile station device and the network. Thededicated control channel (DCCH) is used by a mobile station devicehaving an RRC connection. The dedicated traffic channel (DTCH), which isa point-to-point bidirectional channel and is a channel dedicated tosingle mobile station device, is used to transfer user information(unicast data).

Next, the transport channels are described. The broadcast channel (BCH)is broadcasted to the entire cell in a fixed or predefined transmissionmanner. The downlink shared channel (DL-SCH) supports a hybrid automaticrepeat request (HARQ), dynamic adaptation radio link control, anddiscontinuous reception (DRX), and is broadcasted to the entire cell.

The paging channel (PCH) supports the DRX, and needs to be broadcastedto the entire cell. The paging channel (PCH) is mapped to a physicalresource which is dynamically used with respect to a traffic channel orother control channels, more specifically, the physical downlink sharedchannel (PDSCH).

Next, the physical channels are described. The physical broadcastchannel (PBCH) maps the broadcast channel (BCH) in a 40-millisecondcycle. The physical downlink control channel (PDCCH) is a channel usedto notify the mobile station device of radio resource assignment(downlink assignment) of the physical downlink shared channel (PDSCH), ahybrid automatic repeat request (HARQ) information for the downlinkdata, and an uplink grant that is radio resource assignment of thephysical uplink shared channel (PUSCH). The physical downlink sharedchannel (PDSCH) is a channel used to transmit the downlink data or thepaging information.

The physical downlink control channel (PDCCH) is allocated on 1st to 3rdsymbol OFDMs from a head of a resource block in one subframe, and thephysical downlink shared channel (PDSCH) is allocated on the rest of theOFDM symbols. One subframe includes two resource blocks, and one frameincludes 10 subframes. One resource block includes 12 subcarriers andseven OFDM symbols.

In a case that the base station device notifies the mobile stationdevice of the radio resource assignment of the physical downlink sharedchannel (PDSCH) on the physical downlink control channel (PDCCH) to themobile station, a region of the physical downlink shared channel (PDSCH)assigned to the mobile station device is the physical downlink sharedchannel (PDSCH) in the same subframe as the physical downlink controlchannel (PDCCH) used to notify the downlink assignment.

Next, channel mapping is described. As illustrated in FIG. 8, in thedownlink, the transport channels are mapped to the physical channels asbelow. The broadcast channel (BCH) is mapped to the physical broadcastchannel (PBCH). The paging channel (PCH) and the downlink shared channel(DL-SCH) are mapped to the physical downlink shared channel (PDSCH). Thephysical downlink control channel (PDCCH) is used as the dedicatedphysical channels.

In the downlink, the logical channels are mapped to the transportchannels as below. The paging control channel (PCCH) is mapped to thepaging channel (PCH). The broadcast control channel (BCCH) is mapped tothe broadcast channel (BCH) and the downlink shared channel (DL-SCH).The common control channel (CCCH), the dedicated control channel (DCCH),and the dedicated traffic channel (DTCH) are mapped to the downlinkshared channel (DL-SCH).

FIG. 9 is a diagram illustrating an uplink channel configuration in LTE.Each of uplink channels illustrated in FIG. 9 is consisted of logicalchannels, transport channels, and physical channels. The respectivechannels are defined similar to the downlink channels.

The uplink logical channels include a common control channel (CCCH), adedicated control channel (DCCH), and a dedicated traffic channel(DTCH).

The uplink transport channels include an uplink shared channel (UL-SCH)and a random access channel (RACH).

The uplink physical channels include a physical uplink control channel(PUCCH), a physical uplink shared channel (PUSCH), and a physical randomaccess channel (PRACH). These channels are transmitted and receivedbetween a base station device and a mobile station.

Next, the logical channels are described. The common control channel(CCCH), which is a channel used to transmit control information betweenthe mobile station device and the network, is used by a mobile stationdevice not having a radio resource control (RRC) connection with thenetwork.

The dedicated control channel (DCCH), which is a point-to-pointbidirectional channel, is used to transmit the individual controlinformation between the mobile station device and the network. Thededicated control channel (DCCH) is used by a mobile station devicehaving a RRC connection. The dedicated traffic channel (DTCH), which isa point-to-point bidirectional channel and is a channel dedicated tosingle mobile station device, is used to transfer user information(unicast data).

Next, the transport channels are described. The uplink shared channel(UL-SCH) supports a hybrid automatic repeat request (HARQ), dynamicadaptation radio link control, discontinuous transmission (DTX). Therandom access channel (RACH) is used to transmit limited controlinformation.

Next, the physical channels are described. The physical uplink controlchannel (PUCCH) is a channel used to notify the base station device ofresponse information (ACK (acknowledge)/NACK (negative acknowledge)) forthe downlink data, downlink radio quality information, and an uplinkdata transmission request (scheduling request: SR). The physical uplinkshared channel (PUSCH) is a channel used to transmit the uplink data.The physical random access channel (PRACH) is mainly used for randomaccess preamble transmission for acquiring transmission timinginformation (transmission timing command) from the mobile station deviceto the base station device. The random access preamble transmission isperformed in the random access procedure.

Next, channel mapping is described. As illustrated in FIG. 9, in theuplink, the transport channels are mapped to the physical channels asbelow. The uplink shared channel (UL-SCH) is mapped to the physicaluplink shared channel (PUSCH). The random access channel (RACH) ismapped to the physical random access channel (PRACH). The physicaluplink control channel (PUCCH) is used as the dedicated physicalchannels.

In the uplink, the logical channels are mapped to the transport channelsas below. The common control channel (CCCH), the dedicated controlchannel (DCCH), and the dedicated traffic channel (DTCH) are mapped tothe uplink shared channel (UL-SCH).

FIG. 10 illustrates a protocol stack for dealing with control data forthe mobile station device and base station device in LTE. FIG. 11illustrates a protocol stack for dealing with user data for the mobilestation device and base station device in LTE. FIG. 10 and FIG. 11 aredescribed below.

The physical layer (PHY layer) uses the physical channels to provide atransmission service to a higher layer. The PHY layer is connected withthe higher medium access control (MAC) layer via the transport channels.The data is moved via the transport channels between layers, the MAClayer and the PHY layer. The data is transmitted and received via thephysical channels between the PHY layers of the mobile station deviceand the base station device. An entity playing a role in each layer maybe provided in plural in each layer.

The MAC layer maps various logical channels to the various transportchannels. The MAC layer is connected with a higher radio link controllayer (RLC layer) via the logical channels. The logical channels areroughly classified depending on a kind of the transmitted information,specifically, classified into the control channels transmitting thecontrol information and the traffic channels transmitting the userinformation. The MAC layer has a function to control the PHY layer inorder to perform the discontinuous reception and transmission (DRX/DTX),a function to notify transmit power information, and a function toperform the HARQ control.

The MAC layer has a function to notify of a data volume in atransmission buffer corresponding to each of the logical channels(buffer status report (BSR)), and a function to request for a radioresource for transmitting the uplink data (scheduling request). The MAClayer performs the random access procedure in a case of an initialaccess or the scheduling request.

The RLC layer performs segmentation or concatenation of the datareceived from the higher layer to adjust its data size so that a lowerlayer can appropriately transmit the data. The RLC layer also has afunction to guarantee QoS (quality of service) required for each data.In other words, the RLC layer has a function of data re-transmissioncontrol or the like.

A packet data convergence protocol layer (PDCP layer) has a headercompression function to compress unnecessary control information inorder to efficiently transmit an IP packet, which is the user data, in aradio segment. The PDCP layer also has a data encryption function.

In a radio resource control layer (RRC layer), only the controlinformation is defined. The RRC layer performs configuration andreconfiguration of radio bearers (RBs) to control the logical channels,the transport channels and the physical channels. The RBs are classifiedinto a signaling radio bearer (SRB) and a data radio bearer (DRB), andthe SRB is used as a path for transmitting an RRC message that is thecontrol information. The DRB is used as a path for transmitting the userinformation. The RBs are configured between the RRC layers of the basestation device and mobile station device.

The PHY layer corresponds to a physical layer as the first layer in thelayered structure of the generally known open systems interconnection(OSI) model. The MAC layer, the RLC layer, and the PDCP layer correspondto a data link layer as the second layer in the OSI model. The RRC layercorresponds to a network layer as the third layer in the OSI model.

The random access procedures are described. The random access proceduresinclude two access procedures of a contention based random accessprocedure and a non-contention based random access procedure (NPL 1).

FIG. 12 is a diagram illustrating a contention based random accessprocedure. The contention based random access procedure is a randomaccess where contention (collision) possibly occurs between the mobilestation devices, and is used at an initial access from a state of notconnecting (communicating) with the base station device, or for ascheduling request in a case that the uplink data transmission occurs inthe mobile station device in a state out of uplink synchronization evenduring connecting with the base station device.

FIG. 13 is a diagram illustrating a non-contention based random accessprocedure. The non-contention based random access procedure is a randomaccess where contention does not occur between the mobile stationdevices, and the mobile station device is instructed by the base stationdevice to start a random access in a special case, such as a case inwhich handover or the transmission timing of the mobile station deviceis not valid for obtaining the uplink synchronization between the mobilestation device and the base station device when the base station deviceand the mobile station device are out of the uplink synchronization eventhough the base station device and the mobile station device areconnected to each other (NPL 1). The non-contention based random accessprocedure is instructed through a message of the radio resource control(RRC) layer (layer 3) and the control data of the physical downlinkcontrol channel (PDCCH). The non-contention based random accessprocedure being instructed through the control data of the physicaldownlink control channel (PDCCH) is also referred to as a PDCCH order(random access instruction).

The contention based random access procedure is briefly described withreference to FIG. 12. First, a mobile station device 1-1 transmits arandom access preamble to a base station device 5 (message 1: (1), stepS1). The base station device 5 receiving the random access preambletransmits a response (random access response message) with respect tothe random access preamble to the mobile station device 1-1 (message 2:(2), step S2). The mobile station device 1-1 transmits the message ofthe higher layer (layer 2/layer 3) on the basis of an uplink grantincluded in the random access response message (message 3: (3), stepS3).

The base station device 5 transmits a contention resolution message tothe mobile station device 1-1 having received the higher layer messagesat (3) (message 4: (4), step S4). The contention based random access isalso referred to as random preamble transmission.

The non-contention based random access procedure is briefly describedwith reference to FIG. 13. First, the base station device 5 notifies themobile station device 1-1 of a preamble ID (or a sequence number) and ofa random access channel number to be used (message 0: (1′), step S11).The mobile station device 1-1 transmits a random access preamble of thespecified preamble ID to the specified random access channel (RACH)(message 1: (2′), step S12). The base station device 5 receiving therandom access preamble transmits a response (random access responsemessage) with respect to the random access preamble to the mobilestation device 1-1 (message 2: (3′), step S13). However, if a value ofthe notified preamble ID is zero, the contention based random accessprocedure is performed. The non-contention based random access is alsoreferred to as dedicated preamble transmission.

A procedure of connecting the mobile station device 1-1 to the basestation device 5 is described with reference to FIG. 12. First, themobile station device 1-1 acquires system information of the basestation device 5 from the physical broadcast channel (PBCH) or the like,and performs the random access procedure based on random access-relatedinformation included in the system information to connect to the basestation device 5. The mobile station device 1-1 generates the randomaccess preamble from the random access-related information or the likein the system information. The mobile station device 1-1 transmits therandom access preamble on the random access channel (RACH) (message 1:(1)).

Once the base station device 5 detects the random access preamble fromthe mobile station device 1-1, the base station device 5 calculates atransmission timing shift amount between the mobile station device 1-1and the base station device 5 from the random access preamble, performsscheduling (specifies an uplink radio resource location (a location ofthe physical uplink shared channel (PUSCH)), a transmission format(message size), or the like) in order to transmit the layer 2 (L2)/layer3 (L3) message, assigns a cell-radio network temporary identity(temporary C-RNTI: mobile station device identification information),allocates, to the physical downlink control channel (PDCCH), a randomaccess-radio network temporary identity (RA-RNTI: random access responseidentification information) indicating a response (random accessresponse message) directed to the mobile station device 1-1 havingtransmitted the random access preamble of the random access channel(RACH), and transmits, to the physical downlink shared channel (PDSCH),the random access response message including the transmission timinginformation, the uplink grant, the temporary C-RNTI, and information ofthe received random access preamble (message 2: (2)).

Once the mobile station device 1-1 detects the RA-RNTI in the physicaldownlink control channel (PDCCH), the mobile station device 1-1 checkscontent of the random access response message on the physical downlinkshared channel (PDSCH), and if the transmitted information of the randomaccess preamble is included in the random access response message, themobile station device 1-1 adjusts uplink transmission timing based onthe transmission timing information, and transmits the L2/L3 messageincluding the information identifying the mobile station device 1-1 suchas the C-RNTI (or the temporary C-RNTI) or international mobilesubscriber identity (IMSI) in the scheduled radio resource and thetransmission format (message 3: (3)).

In a case that the mobile station device 1-1 adjusts the transmissiontiming, the mobile station device 1-1 starts a transmission timingtimer. While the transmission timing timer is operating (or running),the transmission timing is valid, and in a case that the transmissiontiming timer expires or stops, the transmission timing is invalid. Whilethe transmission timing is valid, the mobile station device 1-1 is ableto perform data transmission to the base station device 5, and if thetransmission timing is invalid, the mobile station device 1-1 is able totransmit only the random access preamble. A time period while thetransmission timing is valid is also referred to as an uplinksynchronous state, and a time period while the transmission timing isnot valid is also referred to as an uplink asynchronous state.

Once the base station device 5 receives the L2/L3 message from themobile station device 1-1, the base station device 5 uses the C-RNTI (orthe temporary C-RNTI) or IMSI included in the received L2/L3 message totransmit, to the mobile station device 1-1, a contention resolutionmessage for determining whether or not a contention (collision) occursbetween the mobile station devices 1-1 to 1-3 (message 4: (4)).

Once the mobile station device 1-1 transmits the L2/L3 message, themobile station device 1-1 starts a contention resolution timer. In acase that the mobile station device 1-1 receives the contentionresolution message while the contention resolution timer operates, themobile station device 1-1 terminates the random access procedure.

In a case that the mobile station device 1-1 does not detect, during arandom access response window, the random access response messageincluding the preamble ID corresponding to the transmitted random accesspreamble, or fails to transmit the message 3, or does not detect theidentification information of the mobile station device 1-1 itself inthe contention resolution message until the contention resolution timerexpires, the mobile station device 1-1 starts again from thetransmission of the random access preamble (message 1: (1)).

Then, if the number of transmissions of the random access preambleexceeds the maximum number of transmissions of the random accesspreamble indicated by the system information, the mobile station device1-1 determines a radio link failure and performs connectionre-establishment processing. After a success in the random accessprocedure, the control data for connection is further communicatedbetween the base station device 5 and the mobile station device 1-1. Atthis time, the base station device 5 notifies the mobile station device1-1 of the uplink reference signal to be individually assigned, andallocation information of the physical uplink control channel (PUCCH).

The uplink transmission timing after the random access procedurecompletion is updated by the base station device 5 measuring the uplinkreference signal (sounding reference signal or demodulation referencesignal) transmitted from the mobile station device 1-1 to calculate thetransmission timing, and notifying the mobile station device 1-1 of thetransmission timing message including the calculated transmission timinginformation.

When the mobile station device 1-1 updates the transmission timingindicated in the transmission timing message notified by the basestation device 5, the mobile station device 1-1 restarts thetransmission timing timer. The base station device 5 also holds atransmission timing timer the same as the timer in the mobile stationdevice 1-1, and if the base station device 5 transmits the transmissiontiming information, the base station device 5 starts or restarts thetransmission timing timer. In this way, the base station device 5 andthe mobile station device 1-1 manage the uplink synchronous state. Ifthe transmission timing timer expires, or if the transmission timingtimer does not operate, the transmission timing is invalid.

In 3GPP, further evolved LTE, LTE-Advanced has been discussed. InLTE-Advanced, it is assumed that a band having the maximum bandwidth of100 MHz is used in each of the uplink and the downlink to performcommunication at a transmission rate of 1 Gbps or greater in thedownlink and 500 Mbps or greater in the uplink at a maximum.

In LTE-Advanced, it has been considered that multiple bands of 20 MHz orless in LTE are aggregated such that the mobile station device of LTEcan be also accommodated to attain the maximum band of 100 MHz. InLTE-Advanced, one band of 20 MHz or less in LTE is referred to as acomponent carrier (CC) (NPL 1).

One downlink component carrier and one uplink component carrier arecombined to configure one cell. Even only one downlink component carriercan configure one cell. Multiple cells being aggregated so that the basestation device and the mobile station device communicate with each othervia the multiple cells is referred to as carrier aggregation.

One base station device assigns multiple cells suitable for acommunication capability or communication condition of the mobilestation device to communicate with the mobile station device via theassigned multiple cells. The multiple cells assigned to the mobilestation device are classified into one primary cell (PCell) andsecondary cells (SCells) other than the primary cell. A specialfunction, such as physical uplink control channel (PUCCH) allocation, isconfigured in the primary cell.

On the other hand, in LTE-Advanced, cost reduction has been studied forthe mobile station device for a special category such as a mobilestation device supporting machine type communication (MTC) or machine tomachine communication (M2M) (NPL 2). Hereinafter, the MTC/M2M mobilestation device or the MTC/M2M communication device is also referred toas a machine type communication user equipment (MTCUE).

In order to attain a low-cost MTCUE complying with the LTE standard andthe LTE-Advanced standard, there has been proposed a cost reductionmethod including narrowing a transmission and reception bandwidth,reduction in the number of antenna ports/the number of RF chains,reduction in a transmitted and received data transfer rate, employmentof a half-duplex frequency division duplex mode, reduction in transmitand receive power, and extension of a discontinuous reception interval.There has been suggested that reduction of maximum bandwidth iseffective in a transmission and reception RF circuit and transmissionand reception baseband circuit of the MTCUE as a method in order toattain a low-cost MTCUE.

In order to compensate degradation of reception and transmissioncharacteristics due to the reduction in the number of antenna ports orthe like, it has been considered that the downlink data or the downlinksignal is repeatedly transmitted to the MTCUE for a single datatransmission, and the MTCUE repeatedly transmits the uplink data or theuplink signal to the base station device for a single data transmission.

In the study on the MTC, coverage enhancement has been studied forenhancing a transmission and reception coverage of the MTCUE, inaddition to the study for the cost reduction. In order to reduce thetransmit and receive power and enhance the coverage, it has beenconsidered that the base station device repeatedly transmits thedownlink data or the downlink signal to the MTCUE for a single datatransmission, and the MTCUE repeatedly transmits the uplink data or theuplink signal to the base station device for a single data transmission.

The MTCUE repeatedly receives the data from the base station device fora single data reception, and adds up the repeatedly received data todemodulate the data. The base station device also repeatedly receivesthe data from the MTCUE, and adds up the repeatedly received data todemodulate the data.

For example, the base station device repeatedly transmits the physicalbroadcast channel (PBCH) to the MTCUE multiple times within 40 ms. Thebase station device repeatedly transmits the physical downlink sharedchannel (PDSCH), the physical downlink control channel (PDCCH), and anenhanced physical downlink control channel (EPDCCH) to the MTCUEmultiple times. The MTCUE transmits the physical uplink shared channel(PUSCH), the physical uplink control channel (PUCCH), and the like tothe base station device multiple times.

In the random access procedure, the MTCUE repeatedly transmits the samerandom access preamble on multiple physical random access channels(PRACHs). The base station device receiving the random access preamblerepeatedly transmits a random access response message. The message 3 andthe contention resolution are also repeatedly transmitted. The basestation device notifies the MTCUEs in the cell on the broadcast channel(BCH) or individually notifies the MTCUE of the number of repetitivetransmissions and receptions (NPL 3).

For example, the number of repetitions of the random access preambletransmission is notified on the broadcast channel (BCH). It has beenalso studied that the number of repetitions of the random accesspreamble transmission includes multiple kinds of the numbers ofrepetitive transmissions such that the MTCUE can select one number ofrepetitive transmissions from the multiple kinds of the numbers ofrepetitive transmissions. A single repetitive transmission is alsoreferred to as a single attempt.

Control of repetition with respect to the physical downlink controlchannel (PDCCH) reception, the enhanced physical downlink controlchannel (EPDCCH) reception, the physical uplink control channel (PUCCH)transmission, and the physical random access channel (PRACH) (or randomaccess preamble) transmission is also referred to as repetition orrepetition control, and control of repetition with respect to thephysical downlink shared channel (PDSCH) reception and the physicaluplink shared channel (PUSCH) transmission is also referred to asbundling or bundling control.

When the bundling is configured, a bundle size defines the number ofsubframes in one bundle. A bundling operation relies on a HARQ entityinvoking an identical HARQ process for the respective transmissionsconstituting the identical bundle. HARQ retransmission is non-adaptivein one bundle, and is triggered depending on the bundle size withoutwaiting for a feedback from the last transmission. The HARQ feedback forone bundle is received (HARQ-ACK for PUSCH) or transmitted (HARQ-ACK forPDSCH) received by the terminal device with respect to only the lastsubframe in the bundle. The bundling processing is performed in the MAClayer.

The mobile station device designed for the machine type communication(MTC) or machine to machine communication (M2M) and supporting the costreduction and/or coverage enhancement, or the MTC/M2M communicationdevice is described below as a machine type communication user equipment(MTCUE). However, an application of such a mobile station device is notlimited to the machine type communication or the machine to machinecommunication. A mobile station device not characterized by the costreduction nor the coverage enhancement is described below merely as amobile station device.

EMBODIMENT

Description of Configuration

FIG. 1 is a diagram illustrating a configuration of an MTCUE accordingto an embodiment of the present invention. MTCUEs 3-1 to 3-3 eachinclude a data generation unit 101, a transmission data storage unit103, a transmission HARQ processing unit 105, a transmission processingunit 107, a radio unit 109, a reception processing unit 111, a receptionHARQ processing unit 113, a MAC information extraction unit 115, a PHYcontrol unit 117, a MAC control unit 119, a data processing unit 121,and an RRC control unit 123.

User data from a higher layer and control data from the RRC control unit123 are input to the data generation unit 101. The data generation unit101 has functions of the PDCP layer and RLC layer. The data generationunit 101 performs processing of header compression, data encryption,data segmentation and concatenation of the IP packet of the user data orthe like to adjust a data size. The data generation unit 101 outputs theprocessed data to the transmission data storage unit 103.

The transmission data storage unit 103 accumulates the data input fromthe data generation unit 101, and outputs the data specified on thebasis of an instruction from the MAC control unit 119, by a specifieddata volume, to the transmission HARQ processing unit 105. Thetransmission data storage unit 103 outputs information on the datavolume of the accumulated data to the MAC control unit 119.

The transmission HARQ processing unit 105 encodes the input data, andperforms a puncture process on the encoded data. The transmission HARQprocessing unit 105 outputs the punctured data to the transmissionprocessing unit 107, and stores the encoded data. If the transmissionHARQ processing unit 105 is instructed by the MAC control unit 119 toretransmit the data, the transmission HARQ processing unit 105 performs,on the stored (buffered) encoded data, a puncture process different fromthe puncture performed last time, and outputs the punctured data to thetransmission processing unit 107. If the transmission HARQ processingunit 105 is instructed by the MAC control unit 119 to delete the data,the transmission HARQ processing unit 105 deletes the data correspondingto the specified cell.

The transmission processing unit 107 modulates and encodes the datainput from the transmission HARQ processing unit 105. The transmissionprocessing unit 107 performs discrete Fourier transform (DFT)-inversefast Fourier transform (IFFT) processing on the modulated and encodeddata, and, after this processing, inserts a cyclic prefix (CP),allocates the data after the CP insertion on the physical uplink sharedchannel (PUSCH) in each uplink component carrier (cell), and outputs tothe radio unit 109.

If the transmission processing unit 107 is instructed by the PHY controlunit 117 to response to the reception data, the transmission processingunit 107 generates an ACK or NACK signal, allocates the generated signalon the physical uplink control channel (PUCCH), and outputs to the radiounit 109. If the transmission processing unit 107 is instructed by thePHY control unit 117 to transmit the random access preamble, thetransmission processing unit 107 generates the random access preamble,allocates the generated signal on the physical random access channel(PRACH), and outputs to the radio unit 109. The transmission processingunit 107 performs the repetitive transmission processing on the basis ofthe instruction from the PHY control 117.

The radio unit 109 up-converts the date input from the transmissionprocessing unit 107 into data of a radio frequency according totransmission location information (transmission cell information)specified by the PHY control unit 117, adjusts transmit power, andtransmits the data from a transmission antenna. The radio unit 109down-converts a radio signal received through a reception antenna tooutput to the reception processing unit 111. The radio unit 109configures the transmission timing information received from the PHYcontrol unit 117 as the uplink transmission timing.

The reception processing unit 111 performs fast Fourier transform (FFT)processing, decoding, demodulation processing, and the like on thesignal input from the radio unit 109. If the reception processing unit111 demodulates the physical downlink control channel (PDCCH) or theenhanced physical downlink control channel (EPDCCH) to detect downlinkassignment information for the device itself, the reception processingunit 111 demodulates the physical downlink shared channel (PDSCH) on thebasis of the downlink assignment information, and outputs acquisition ofthe downlink assignment information to the MAC control unit 119.

The reception processing unit 111 outputs the data of the demodulatedphysical downlink shared channel (PDSCH) to the reception HARQprocessing unit 113. If the reception processing unit 111 demodulatesthe physical downlink control channel (PDCCH) or the enhanced physicaldownlink control channel (EPDCCH) to detect the uplink grant and theresponse information (ACK/NACK) to the uplink transmission data, thereception processing unit 111 outputs the acquired response informationto the MAC control unit 119. The uplink grant includes a data modulatingand encoding scheme, the data size information, the HARQ information,the transmission location information and the like. The receptionprocessing unit 111 performs the repetitive reception processing on thebasis of the instruction from the PHY control 117.

The reception HARQ processing unit 113 performs decode processing on thedata input from the reception processing unit 111, and in a case ofsucceeding in the decode processing, outputs the data to the MACinformation extraction unit 115. If the reception HARQ processing unit113 fails in the decode processing on the input data, the reception HARQprocessing unit 113 stores the data on which the decode processing hasfailed. If the reception HARQ processing unit 113 receives retransmitteddata, the reception HARQ processing unit 113 synthesizes the stored dataand the retransmitted data to perform the decode processing. Thereception HARQ processing unit 113 notifies the MAC control unit 119 ofa success or failure of the decode processing on the input data.

The MAC information extraction unit 115 extracts control information ofa medium access control layer (MAC layer) from the data input from thereception HARQ processing unit 113, and outputs the extracted MACcontrol information (MAC control element) to the MAC control unit 119.The MAC information extraction unit 115 outputs the rest of the data tothe data processing unit 121. The data processing unit 121, which hasfunctions of the PDCP layer and RLC layer, performs a function todecompress (restore) a compressed IP header or a function to decode theencrypted data, and processing of data segmentation and concatenation orthe like to reconstruct an original form of the data. The dataprocessing unit 121 divides the data into the RRC message and the userdata, and outputs the RRC message and the user data to the RRC controlunit 123 and the higher layer, respectively.

The PHY control unit 117 controls the transmission processing unit 107,the radio unit 109, and the reception processing unit 111 according toan instruction from the MAC control unit 119. The PHY control unit 117is notified by the MAC control unit 119 of the modulating and encodingscheme and the transmit power information, and notifies the transmissionprocessing unit 107 and the radio unit 109 of the modulating andencoding scheme and the transmit power information, respectively.

If the PHY control unit 117 is notified by the MAC control unit 119 of aPDSCH/PUSCH repetition level or the number of repetitions, the PHYcontrol unit 117 controls the transmission processing unit 107 and thereception processing unit 111 to perform the repetitive transmissions orthe repetitive receptions by the number of repetitions based on thenotified PDSCH/PUSCH repetition level.

If the PHY control unit 117 is notified by the MAC control unit 119 of aPRACH repetition level or the number of repetitions, the PHY controlunit 117 controls the transmission processing unit 107 and the receptionprocessing unit 111 to perform the repetitive transmissions of therandom access preamble or the repetitive receptions of the random accessresponse by the number of repetitions based on the notified PRACHrepetition level.

The MAC control unit 119, which has a function of the MAC layer,controls the MAC layer on the basis of information acquired from the RRCcontrol unit 123, the lower layer, or the like. The MAC control unit 119determines a data transmission priority order based on a datatransmission control configuration specified by the RRC control unit123, data volume information acquired from the transmission data storageunit 103, and the uplink grant acquired from the reception processingunit 111, and notifies the transmission data storage unit 103 ofinformation relating to the data to transmit. The MAC control unit 119notifies the transmission HARQ processing unit 105 of the HARQinformation, and outputs the modulating and encoding scheme to the PHYcontrol unit 117.

The MAC control unit 119 acquires the response information for theuplink transmission data from the reception processing unit 111, and ifthe response information indicates the NACK (negative response), the MACcontrol unit 119 instructs the transmission HARQ processing unit 105 andthe PHY control unit 117 to retransmit the data. If the MAC control unit119 acquires information concerning the success/failure of the decodeprocessing on the data from the reception HARQ processing unit 113, theMAC control unit 119 instructs the PHY control unit 117 to transmit theACK or NACK signal.

The MAC control unit 119 performs the random access procedure. The MACcontrol unit 119 performs processing such as selecting the random accesspreamble, receiving the random access response message, and managing thecontention resolution timer. The MAC control unit 119 notifies the PHYcontrol unit 117 of information required for the random access preambletransmission, random access response message reception, message 3transmission, and contention resolution reception.

The MAC control unit 119 acquires transmission timing timer informationfrom the RRC control unit 123. The MAC control unit 119 uses thetransmission timing timer to manage validity or invalidity of the uplinktransmission timing. The MAC control unit 119 outputs to the PHY controlunit 117 the transmission timing information (transmission timingcommand) included in the transmission timing message among the MACcontrol information input from the MAC information extraction unit 115.If the MAC control unit 119 applies the transmission timing, the MACcontrol unit 119 starts or restarts the transmission timing timer.

In a case of expiration of the transmission timing timer, the MACcontrol unit 119 instructs the transmission HARQ processing unit 105 todelete the stored data. The MAC control unit 119 notifies the RRCcontrol unit 123 to release the physical uplink control channel (PUCCH)and the radio resource of the uplink sounding reference signal. The MACcontrol unit 119 discards the uplink grant.

The MAC control unit 119 uses a repetition level timer acquired from theRRC control unit 123 to perform the repetition control. If the MACcontrol unit 119 acquires information indicating the PDSCH/PUSCHrepetition level (PDSCH/PUSCH repetition level command) by way of theMAC control information input from the MAC information extraction unit115, the MAC control unit 119 notifies the PHY control unit 117 of thePDSCH/PUSCH repetition level and starts or restarts the repetition leveltimer. Then, if the repetition level timer expires, the MAC control unit119 configures the PDSCH/PUSCH repetition level to a default value. TheMAC control unit 119 may notify the RRC control unit 123 of theexpiration of the repetition level timer.

The MAC control unit 119 generates a buffer status report (BSR) that isvolume information on data accumulated in the transmission data storageunit 103, and outputs to the transmission data storage unit 103. The MACcontrol unit 119 generates a power headroom report (PHR) that is thetransmit power information, and outputs to the transmission data storageunit 103.

The RRC control unit 123 performs various configurations forcommunicating with the base station device 5 such as connectionestablishment or connection release with the base station device 5, andthe data transmission control configuration for the control data anduser data. The RRC control unit 123 communicates the information withthe higher layer in association with the various configurations, andcontrols the lower layer in association with the various configurations.

The RRC control unit 123 creates an RRC message, and outputs the createdRRC message to the data generation unit 101. The RRC control unit 123analyzes the RRC message input from the data processing unit 121. TheRRC control unit 123 creates a message indicating a transmissioncapability of the MTCUE itself, and outputs to the data generation unit101. The RRC control unit 123 outputs information required by the MAClayer to the MAC control unit 119, and outputs information required bythe physical layer to the PHY control unit 117,

If the RRC control unit 123 acquires the system information, the RRCcontrol unit 123 outputs required information for the MAC control unit119 and the PHY control unit 117. If the RRC control unit 123 isnotified by the MAC control unit 119 to release the physical uplinkcontrol channel (PUCCH) or the uplink sounding reference signal, the RRCcontrol unit 123 releases the allocated physical uplink control channel(PUCCH) and uplink sounding reference signal, and instructs the PHYcontrol unit 117 to release the physical uplink control channel (PUCCH)and the uplink sounding reference signal.

If the RRC control unit 123 acquires the system information for theMTCUE, the RRC control unit 123 configures a repetition mode (bundlingmode, repetitive transmission and reception mode). In the case of theMTCUE, the repetition mode may be configured.

If the RRC control unit 123 acquires the information relating to thePDSCH/PUSCH repetition, the RRC control unit 123 outputs the number ofrepetitive transmissions and receptions and the repetition level timerinformation which correspond to the repetition level to the MAC controlunit 119 and the PHY control unit 117.

The transmission processing unit 107, the radio unit 109, the receptionprocessing unit 111, and the PHY control unit 117 perform operations ofthe physical layer. The transmission data storage unit 103, thetransmission HARQ processing unit 105, the reception HARQ processingunit 113, the MAC information extraction unit 115, and the MAC controlunit 119 perform operations of the MAC layer. The data generation unit101 and the data processing unit 121 perform operations of the RLC layerand the PDCP layer. The RRC control unit 123 performs operations of theRRC layer.

FIG. 2 is a diagram illustrating a configuration of the base stationdevice according to the embodiment of the present invention. The basestation device 5 includes a data generation unit 201, a transmissiondata storage unit 203, a transmission HARQ processing unit 205, atransmission processing unit 207, a radio unit 209, a receptionprocessing unit 211, a reception HARQ processing unit 213, a MACinformation extraction unit 215, a PHY control unit 217, a MAC controlunit 219, a data processing unit 221, and an RRC control unit 223.

User data from a higher layer and control data from the RRC control unit223 are input to the data generation unit 201. The data generation unit201, which has functions of the PDCP layer and RLC layer, performsheader compression or data encryption, and processing of datasegmentation and concatenation of the IP packet of the user data or thelike to adjust a data size. The data generation unit 201 outputs theprocessed data and logical channel information on the data to thetransmission data storage unit 203.

The transmission data storage unit 203 accumulates the data input fromthe data generation unit 201 for each user, and outputs the data of theuser specified on the basis of an instruction from the MAC control unit219, by a specified data volume, to the transmission HARQ processingunit 205. The transmission data storage unit 203 outputs information onthe data volume of the accumulated data to the MAC control unit 219.

The transmission HARQ processing unit 205 encodes the input data, andperforms a puncture process on the encoded data. The transmission HARQprocessing unit 205 outputs the punctured data to the transmissionprocessing unit 207, and stores the encoded data. If the transmissionHARQ processing unit 205 is instructed by the MAC control unit 219 toretransmit the data, the transmission HARQ processing unit 205 performs,on the stored encoded data, a puncture process different from thepuncture performed last time, and outputs the punctured data to thetransmission processing unit 207.

The transmission processing unit 207 modulates and encodes the datainput from the transmission HARQ processing unit 205. The transmissionprocessing unit 207 maps the modulated and encoded data to the signaland channel such as the physical downlink control channel (PDCCH), thedownlink synchronization signal, the physical broadcast channel (PBCH),and the physical downlink shared channel (PDSCH), and performs OFDMsignal processing such as serial-parallel conversion, inverse fastFourier transform (IFFT), and CP insertion on the mapped data togenerate an OFDM signal.

The transmission processing unit 207 outputs the generated OFDM signalto the radio unit 209. If the transmission processing unit 207 isinstructed by the MAC control unit 219 to response to the receptiondata, the transmission processing unit 207 generates an ACK or NACKsignal, allocates the generated signal on the physical downlink controlchannel (PDCCH), and outputs to the radio unit 209. The transmissionprocessing unit 207 performs the repetitive transmission processing onthe basis of the instruction from the PHY control 217.

The radio unit 209 up-converts the date input from the transmissionprocessing unit 207 into data of a radio frequency, adjusts the transmitpower, and transmits the data from a transmission antenna. The radiounit 209 down-converts the radio signal received through a receptionantenna to output to the reception processing unit 211.

The reception processing unit 211 performs fast Fourier transform (FFT)processing, decoding, demodulation processing, and the like on thesignal input from the radio unit 209. The transmission processing unit211 also performs the repetitive reception processing on the basis ofthe instruction from the PHY control 217.

The reception processing unit 211 outputs the data of the physicaluplink shared channel (PUSCH) among the demodulated data to thereception HARQ processing unit 213. The reception processing unit 211outputs to the MAC control unit 219 the response information (ACK/NACK)to the downlink transmission data, downlink radio quality information(CQI), and uplink transmission request information (scheduling request)of the control data acquired from the physical uplink control channel(PUCCH) among the demodulate data. The reception processing unit 211calculates uplink radio quality from the uplink sounding referencesignal of the MTCUE 3-1, and outputs the uplink radio qualityinformation to the RRC control unit 223 and the MAC control unit 219.

The reception processing unit 211 performs processing of detecting therandom access preamble by the number of repetitions specified by the PHYcontrol unit 217. If the reception processing unit 211 detects therandom access preamble, the reception processing unit 211 calculatestransmission timing from the detected random access preamble, andoutputs a random access preamble ID of the detected random accesspreamble and the calculated transmission timing to the MAC control unit219. The reception processing unit 211 calculates a transmission timingfrom the uplink reference signal, and outputs the calculatedtransmission timing to the MAC control unit 219.

The reception HARQ processing unit 213 performs decode processing on thedata input from the reception processing unit 211, and in a case ofsucceeding in the decode processing, outputs the data to the MACinformation extraction unit 215. If the reception HARQ processing unit213 fails in the decode processing on the input data, the reception HARQprocessing unit 213 stores the data on which the decode processing hasfailed. If the reception HARQ processing unit 213 receives retransmitteddata, it synthesizes the stored data and the retransmitted data toperform the decode processing. The reception HARQ processing unit 213notifies the MAC control unit 219 of a success or failure of the decodeprocessing on the input data. If the reception HARQ processing unit 213is instructed by the MAC control unit 219 to delete the data, thereception HARQ processing unit 213 deletes the data corresponding to thespecified cell.

The MAC information extraction unit 215 extracts control information ofa MAC layer from the data input from the reception HARQ processing unit213, and outputs the extracted control information to the MAC controlunit 219.

The MAC information extraction unit 215 outputs the rest of the data tothe data processing unit 221. The data processing unit 221, which hasfunctions of the PDCP layer and RLC layer, performs a function todecompress (restore) a compressed IP header or a function to decode theencrypted data, and processing of data segmentation and concatenation orthe like to reconstruct an original form of the data. The dataprocessing unit 221 divides the data into the RRC message and the userdata, and outputs the RRC message and the user data to the RRC controlunit 223 and the higher layer, respectively.

The PHY control unit 217 controls the transmission processing unit 207,the radio unit 209, and the reception processing unit 211 according toan instruction from the MAC control unit 219. The PHY control unit 217is notified by the MAC control unit 219 of the modulating and encodingscheme and the transmit power information, and notifies the transmissionprocessing unit 207 and the radio unit 209 of the modulating andencoding scheme and the transmit power information, respectively.

The PHY control unit 217 notifies the reception processing unit 211 ofinformation required for reception processing of the random accesspreamble from information relating to the random access procedure.

If the PHY control unit 217 is notified by the MAC control unit 219 of aPDSCH/PUSCH repetition level or the number of repetitions, the PHYcontrol unit 217 controls the transmission processing unit 207 and thereception processing unit 211 to perform the repetitive transmissions orthe repetitive receptions by the number of repetitions based on thenotified repetition level.

The MAC control unit 219, which has a function of the MAC layer,controls the MAC layer on the basis of information acquired from the RRCcontrol unit 223, the lower layer, or the like. The MAC control unit 219performs downlink and uplink scheduling processing.

The MAC control unit 219 performs the downlink and uplink schedulingprocessing on the basis of the response information (ACK/NACK) to thedownlink transmission data, the downlink radio quality information(CQI), the uplink radio quality information, and the uplink transmissionrequest information (scheduling request) which are input from thereception processing unit 211, the control information which is inputfrom the MAC information extraction unit 215, and the data volumeinformation for each user, the number of repetitive transmissions andreceptions, and a reception operation state of the MTCUE 3-1 which areacquired from the transmission data storage unit 203. The MAC controlunit 219 outputs a scheduling result to the transmission processing unit207. The MAC control unit 219 determines the reception operation stateof the MTCUE 3-1 on the basis of a discontinuous reception parameteracquired from the RRC control unit 223.

The MAC control unit 219 acquires the response information for theuplink transmission data from the reception processing unit 211, and ifthe response information indicates the NACK (negative response), the MACcontrol unit 219 instructs the transmission HARQ processing unit 205 andthe transmission processing unit 207 to retransmit the data. If the MACcontrol unit 219 acquires the information concerning the success/failureof the decode processing on the data from the reception HARQ processingunit 213, the MAC control unit 219 instructs the transmission processingunit 207 to transmit the ACK or NACK signal.

If the MAC control unit 219 acquires the random access preamble ID andthe transmission timing from the reception processing unit 211, the MACcontrol unit 219 creates a random access response message and outputsthe random access response message to the transmission data storage unit203. The random access response message may include the PDSCH/PUSCHrepetition level command. If the MAC control unit 219 acquires thetransmission timing from the reception processing unit 211, the MACcontrol unit 219 creates a transmission timing message including thetransmission timing and outputs the transmission timing message to thetransmission data storage unit 203.

The MAC control unit 219 determines the MTCUE or the mobile stationdevice on the basis of the random access preamble ID notified by thereception processing unit 211. It is determined whether the repetitivetransmission or the repetitive reception is required for transmission ofthe random access response message, transmission of the contentionresolution, and reception of the message 3 to schedule the random accessresponse message transmission, the contention resolution transmission,and the message 3 reception.

The MAC control unit 219 manages the uplink transmission timing. The MACcontrol unit 219 uses the transmission timing timer to manage the uplinktransmission timing for the MTCUE 3-1. If the MAC control unit 219transmits the transmission timing message to the MTCUE 3-1, the MACcontrol unit 219 starts or restarts the transmission timing timer.

The MAC control unit 219 instructs the reception HARQ processing unit213 to cause the MTCUE 3-1 to delete the data stored in the MTCUE 3-1.The MAC control unit 219 notifies the RRC control unit 223 to releasethe physical uplink control channel (PUCCH) and radio resource of theuplink sounding reference signal allocated to the MTCUE 3-1. The MACcontrol unit 219 stops scheduling the uplink data for the MTCUE 3-1.

The MAC control unit 219 uses a repetition level timer acquired from theRRC control unit 223 to control the repetitive transmission andreception.

The MAC control unit 219 determines the PDSCH/PUSCH repetition level onthe basis of the uplink radio quality information from the receptionprocessing unit 211 or the downlink radio quality information notifiedby the MTCUE 3-1 (e.g., CQI, RSRP, RSRQ), for example, creates the MACcontrol information including information indicating the PDSCH/PUSCHrepetition level or PDSCH/PUSCH bundling size (hereinafter, referred toas PDSCH/PUSCH repetition level command), and outputs the MAC controlinformation including the PDSCH/PUSCH repetition level command to thetransmission data storage unit 203.

The MAC control unit 219 starts or restarts the repetition level timerin a case that the PDSCH/PUSCH repetition level command is transmitted,or the MTCUE 3-1 receives the PDSCH/PUSCH repetition level command, orthe positive response (ACK) in response to the PDSCH/PUSCH repetitionlevel command is received from the MTCUE 3-1. In the case that thePDSCH/PUSCH repetition level command is transmitted, the MAC controlunit 219 notifies the PHY control unit 219 of a new PDSCH/PUSCHrepetition level.

The MAC control unit 219 may create the MAC control informationinstructing to start or restart the repetition level timer and notifythe MTCUE 3-1 of the information. In a case of expiration of therepetition level timer, the MAC control unit 219 may notify the RRCcontrol unit 223 of the expiration of the repetition level timer. ThePDSCH/PUSCH repetition level may be managed by the RRC control unit 223.

The RRC control unit 223 performs various configurations forcommunicating with the MTCUE 3-1 such as processing of connectionestablishment or connection release with the MTCUE 3-1, and datatransmission control configuration for the control data and user data ofthe MTCUE 3-1, communicates the information with the higher layer inassociation with the various configurations, and controls the lowerlayer in association with the various configurations.

The RRC control unit 223 creates the various RRC messages, and outputsthe created RRC messages to the data generation unit 201. The RRCcontrol unit 223 analyzes the RRC message input from the data processingunit 221.

The RRC control unit 223 creates a message including the systeminformation. The RRC control unit 223 may create a message including thesystem information for the MTCUE 3-1 separately from a message includingthe system information for the mobile station device 1-1.

The RRC control unit 223 notifies the PHY control unit 217 and the MACcontrol unit 219 of the information relating to the random accessprocedure included in the system information.

The RRC control unit 223 creates a message including the informationrelating to the PDSCH/PUSCH repetition level, and outputs to thetransmission data storage unit 203. The information relating to thePDSCH/PUSCH repetition level may include information relating to amaximum repetition level, the number of repetitions corresponding to thePDSCH/PUSCH repetition level, and a value of the repetition level timer.The information relating to the PDSCH/PUSCH repetition level may beconfigured in the system information.

If the message including the information relating to the PDSCH/PUSCHrepetition level is transmitted, the RRC control unit 223 notifies theMAC control unit 219 of the information relating to the maximumPDSCH/PUSCH repetition level, the number of repetitions corresponding tothe PDSCH/PUSCH repetition level, and the value of the repetition leveltimer. If the message including the information relating to thePDSCH/PUSCH repetition level is transmitted, the RRC control unit 223notifies the PHY control unit 217 of the number of repetitionscorresponding to the PDSCH/PUSCH repetition level.

The RRC control unit 223 outputs required information for the MAC layerto the MAC control unit 219, and outputs required information for thephysical layer to the PHY control unit 217. If the RRC control unit 223is notified by the MAC control unit 219 to release the physical uplinkcontrol channel (PUCCH) or the uplink sounding reference signal, the RRCcontrol unit 223 releases the allocated physical uplink control channel(PUCCH) and uplink sounding reference signal, and instructs the PHYcontrol unit 217 to release the physical uplink control channel (PUCCH)and the uplink sounding reference signal.

The transmission processing unit 207, the radio unit 209, and thereception processing unit 211 perform operations of the PHY layer. Thetransmission data storage unit 203, the transmission HARQ processingunit 205, the reception HARQ processing unit 213, the MAC informationextraction unit 215, and the MAC control unit 219 perform operations ofthe MAC layer. The data generation unit 201 and the data processing unit221 perform operations of the RLC layer and the PDCP layer. The RRCcontrol unit 223 performs operations of the RRC layer.

Description of Operations

Assume a radio communication system as described in FIG. 7 to FIG. 13.As illustrated in FIG. 7, the base station device 5 communicates withthe MTCUEs 3-1, 3-2, and 3-3 or the mobile station devices 1-1, 1-2, and1-3.

Operations of the MTCUE 3-1 and the base station device 5 are described.The MTCUE 3-1 performs a cell search to find one cell of the basestation device 5. The MTCUE 3-1 receives the physical broadcast channel(PBCH) of the cell or the like to acquire the system information (thephysical channel configuration, transmit power information, informationrelating to the random access procedure, transmission timing timerinformation or the like of the cell).

The base station device 5 may separate the system information intosystem information broadcasted to the MTCUE 3-1 and system informationbroadcasted to the mobile station device 1-1. The base station device 5may configure contents of the system information broadcasted to theMTCUE 3-1 different from contents of the system information broadcastedto the mobile station device 1-1. For example, the base station device 5broadcasts a system information block type 1 of the system informationof related art to the mobile station device 1-1. The base station device5 may broadcast a system information block type 1A of new systeminformation to the MTCUE 3-1.

Information relating to the random access procedure for the MTCUE 3-1includes random access channel configuration information includingphysical random access channel (PRACH) allocation information and randomaccess preamble generation information, and random access commonconfiguration information including random access preamble selectioninformation, information relating to the PRACH repetition level,transmit power information of the random access preamble, informationrelating to the maximum number of transmissions of the random accesspreamble, information relating to the random access response messagereception, information relating to the message 3 transmission, andinformation relating to the contention resolution message reception.

The information relating to the PRACH repetition level may includeinformation relating to the number of repetitions of the random accesspreamble for each PRACH repetition level. The information relating tothe PRACH repetition level may include information indicating a maximumPRACH repetition level (RepetitionLevelMax). The information relating tothe PRACH repetition level may include information for selecting thePRACH repetition level (e.g., reference symbol received power (RSRP),reference symbol received quality (RSRQ), information relating to athreshold of a path loss). The information relating to the PRACHrepetition level may be included in the random access preamble selectioninformation.

The random access preamble selection information may include groupinformation of the random access preambles (e.g., information on thenumber of random access preambles of each group), and informationindicating a relationship between the group information of the randomaccess preamble and the repetition level as illustrated in FIG. 3.

The random access preamble selection information may include the totalnumber N of the random access preambles the MTCUE 3-1 can select, thenumber M of the random access preambles in a preamble group A or thenumber (N-M) of the random access preambles in a preamble group B, andinformation of the repetition level corresponding to each group. Thenumber of the preamble groups may be three or more.

The information relating to the maximum number of transmissions of therandom access preamble may be the maximum number of transmissions to thenumber of attempts for one repetitive transmission.

Multiple pieces of the information relating to the maximum number oftransmissions of the random access preamble, information relating to therandom access response message reception, information relating to themessage 3 transmission, and information relating to the contentionresolution message reception may be formed corresponding to therepetition levels of the random access preamble.

Information relating to the random access procedure for the mobilestation device 1-1 includes random access channel configurationinformation including physical random access channel (PRACH) allocationinformation and random access preamble generation information, andrandom access common configuration information including random accesspreamble selection information, transmit power information of the randomaccess preamble, information relating to the maximum number oftransmissions of the random access preamble, information relating to therandom access response message reception, information relating to themessage 3 transmission, and information relating to the contentionresolution message reception.

The random access common configuration information of the systeminformation received by the mobile station device 1-1 and the randomaccess common configuration information of the system informationbroadcasted to the MTCUE 3-1 may be independent from each other anddifferent from each other.

The MTCUE 3-1, after receiving the system information for the MTCUE,configures a parameter included in the system information. The MTCUE 3-1configures a mode (operation) for transmission and reception throughrepetition (hereinafter, referred to as a repetition mode). The RRClayer in the MTCUE 3-1 configures the repetition mode on the basis ofconfiguration received from the base station device 5.

The MTCUE 3-1 performs the random access procedure in order to connectto the base station device 5. The MAC layer in the MTCUE 3-1 performsthe random access procedure. The random access procedure in a case thatthe repetition mode is configured in the MTCUE 3-1 is described below.

The MAC layer in the MTCUE 3-1 configures the random access commonconfiguration information. The MAC layer in the MTCUE 3-1 initializes aparameter relating to the random access procedure or the like. Forexample, a preamble transmission counter indicating the number oftransmissions of the random access preamble (or the number of attemptsof the random access preamble) is set to one. A buffer for the message 3transmission is flushed (deleted).

Next, random access resource selection processing for the random accesspreamble transmission is performed. A case that the message 3 is nottransmitted, in other words, a case of a first-time random accesspreamble transmission (an initial attempt of the random access preambletransmission) is described. The MAC layer in the MTCUE 3-1 selects thePRACH repetition level on the basis of a downlink radio channel (ordownlink path loss), and configures the selected PRACH repetition levelin a temporary PRACH repetition level.

The MAC layer in the MTCUE 3-1 configures the maximum number oftransmissions at the PRACH repetition level (e.g., preambleTransMax_r1)corresponding to the temporary PRACH repetition level. The MAC layer inthe MTCUE 3-1 selects a preamble group corresponding to the temporaryPRACH repetition level.

The MAC layer in the MTCUE 3-1 may first select the preamble group, andthen, select the temporary PRACH repetition level.

Next, a case that the message 3 is retransmitted, in other words, a caseof retransmission of the random access preamble (a reattempt of therandom access preamble transmission) is described. The MAC layer in theMTCUE 3-1, in a case of the first-time random access preambletransmission (or in a case of an attempt of the first-time random accesspreamble transmission) at the configured temporary PRACH repetitionlevel, configures the maximum number of transmissions at the PRACHrepetition level corresponding to the temporary PRACH repetition level.The MAC layer in the MTCUE 3-1 selects a preamble group corresponding tothe temporary PRACH repetition level.

The MAC layer in the MTCUE 3-1, not in the case of the first-time randomaccess preamble transmission (or not in the case of the attempt of thefirst-time random access preamble transmission) at the configuredtemporary PRACH repetition level, selects the preamble group used forthe random access preamble transmission corresponding to a first-timemessage 3 transmission.

After selecting the preamble group, the MAC layer in the MTCUE 3-1selects at random a random access preamble from the random accesspreambles belonging to (classified into) the selected preamble group.

The MAC layer in the MTCUE 3-1 selects a random access channel (PRACH)available for transmission. The random access channel (PRACH) availablefor transmission may be a head random access channel (PRACH) startingthe repetitive transmission. The MAC layer in the MTCUE 3-1 calculates areceived power of the random access preamble assumed in the base stationdevice 5.

The MAC layer in the MTCUE 3-1 notifies the physical layer in the MTCUE3-1 of a preamble ID of the selected random access preamble, theselected random access channel (PRACH), the temporary PRACH repetitionlevel (or the number of repetitions corresponding to the temporary PRACHrepetition level), the RA-RNTI (random access response identificationinformation), and the calculated received power of the random accesspreamble.

The physical layer in the MTCUE 3-1 uses the random access preamble IDto generate the random access preamble. The physical layer in the MTCUE3-1 uses the received power of the random access preamble to calculate atransmit power of the random access preamble.

The physical layer in the MTCUE 3-1 transmits the generated randomaccess preamble to the selected random access channel (PRACH) with thecalculated transmit power. The physical layer in the MTCUE 3-1 transmitsthe random access preamble by the number of repetitions corresponding tothe temporary PRACH repetition level.

Then, after the random access preamble transmission, the physical layerin the MTCUE 3-1 monitors the RA-RNTI during the random access responsewindow using the physical downlink control channel (PDCCH) or theenhanced physical downlink control channel (E-PDCCH). If the physicallayer in the MTCUE 3-1 detects the RA-RNTI in the physical downlinkcontrol channel (PDCCH) or the enhanced physical downlink controlchannel (E-PDCCH), the physical layer decodes the physical downlinkcontrol channel shared channel (PDSCH). The physical layer in the MTCUE3-1 notifies the MAC layer in the MTCUE 3-1 of the random accessresponse message obtained by the decoding.

The physical layer in the MTCUE 3-1 may try to receive the physicaldownlink shared channel (PDSCH) transmitted by way of a downlinkresource region corresponding to a radio resource (allocationinformation) of the physical random access channel (PRACH) for therandom access preamble transmitted without using the RA-RNTI.

The physical layer in the MTCUE 3-1 performs the reception processingthrough repetition to the reception processing on the random accessresponse message. In other words, the physical layer in the MTCUE 3-1performs the reception processing through repetition to the physicaldownlink control channel (PDCCH), the enhanced physical downlink controlchannel (E-PDCCH), and/or the physical downlink control channel sharedchannel (PDSCH). The number of repetitive receptions may be configuredcorresponding to the temporary PRACH repetition level.

The MAC layer in the MTCUE 3-1 performs processing as below in a case ofbeing notified of the random access response message reception by thephysical layer in the MTCUE 3-1. If the random access response messageincludes a random access preamble ID corresponding to the transmittedrandom access preamble, the MAC layer in the MTCUE 3-1 determines asuccess in receiving the random access response message. The MAC layerin the MTCUE 3-1 processes the transmission timing information(transmission timing command) included in the random access responsemessage.

The MAC layer in the MTCUE 3-1 processes the PDSCH/PUSCH repetitionlevel command in a case that the repetition mode is set and the randomaccess response message includes the information indicating thePDSCH/PUSCH repetition level (PDSCH/PUSCH repetition level command). TheMAC layer in the MTCUE 3-1 notifies the physical layer in the MTCUE 3-1of the uplink grant included in the random access response message.

In a case that the random access preamble ID is notified through therandom access instruction by the base station device 5 and the MAC layerin the MTCUE 3-1 does not select the random access preamble, the MAClayer in the MTCUE 3-1 determines a success in the random accessprocedure.

In a case that the random access response message is not received duringthe random access response window, or in a case that the received randomaccess response message does not include the preamble ID correspondingto the transmitted random access preamble, the MAC layer in the MTCUE3-1 determines an unsuccess in receiving the random access responsemessage.

In the case of determining the unsuccess in receiving the random accessresponse message and a notification of power ramping suspension is notreceived from the physical layer in the MTCUE 3-1, the preambletransmission counter is incremented by one.

In a case that the value of the preamble transmission counter exceedsthe maximum number of transmissions of the random access preamble (in acase of preambleTransMax_r1+1) at the configured temporary PRACHrepetition level and the temporary PRACH repetition level is at themaximum repetition level (RepetitionLevelMax), the MAC layer in theMTCUE 3-1 notifies the higher layer (e.g., the RRC layer in the MTCUE3-1) of a random access problem.

In a case that the value of the preamble transmission counter exceedsthe maximum number of transmissions of the random access preamble (in acase of preambleTransMax_r1+1) at the configured temporary PRACHrepetition level and the temporary PRACH repetition level is not at themaximum repetition level (RepetitionLevelMax), one is added to thetemporary PRACH repetition level. In other words, the temporary PRACHrepetition level is increased by one level. The preamble transmissioncounter is configured to one. The MAC layer in the MTCUE 3-1 performsagain the random access resource selection processing in order toretransmit the random access preamble.

In a case that the value of the preamble transmission counter does notexceed the maximum number of transmissions of the random access preamble(in a case of preambleTransMax_r1+1) at the configured repetition level,the MAC layer in the MTCUE 3-1 performs again the random access resourceselection processing in order to retransmit the random access preamble.

The RRC layer in the MTCUE 3-1, in a case of being notified of therandom access problem by the MAC layer in the MTCUE 3-1, determines aradio link failure and performs the connection re-establishmentprocedure.

The base station device 5 performs the reception processing of therandom access preamble and the transmission processing of the randomaccess response on an assumption that the MTCUE 3-1 performs the abovetransmission processing of the random access preamble and the abovereception processing of the random access response.

The base station device 5 varies the number of repetitive receptions ofthe random access preamble depending on the preamble ID to detect therandom access preamble transmitted from the MTCUE 3-1.

After detecting the random access preamble, the base station device 5calculates the uplink transmission timing for the MTCUE 3-1 from thereceived random access preamble, creates the random access responsemessage including the transmission timing information including thecalculated transmission timing, the uplink grant for the MTCUE 3-1 totransmit the message 3, the preamble ID of the received random accesspreamble, and the temporary C-RNTI, and repeatedly transmits thephysical downlink shared channel (PDSCH) including the random accessresponse message. The number of repetitive transmissions of the randomaccess response message is configured depending on the received randomaccess preamble.

The base station device 5 may include, in the random access responsemessage, the repetition levels of the PDSCH reception and the PUSCHtransmission, or the numbers of repetitions of the PDSCH reception andthe PUSCH transmission for the MTCUE 3-1 after the random accessresponse reception. Alternatively, the base station device 5 mayinclude, in the random access response message, the number of repetitivetransmissions of the message 3 transmission and the number of repetitivereceptions of the contention resolution reception for the MTCUE 3-1.

The physical layer in the MTCUE 3-1 transmits the message 3 on the basisof the uplink grant. If the random access response message includes thePDSCH/PUSCH repetition level command, the number of repetitivetransmissions of the message 3 may be configured to the number ofrepetitions corresponding to the PDSCH/PUSCH repetition level specifiedin the random access response message. If the random access responsemessage does not specify the PDSCH/PUSCH repetition level, the number ofrepetitive transmissions of the message 3 may be configured to thenumber of repetitions corresponding to the temporary PRACH repetitionlevel.

The MAC layer in the MTCUE 3-1 starts the contention resolution timeronce the message 3 is transmitted. A timer value of the contentionresolution timer may be selected depending on the temporary PRACHrepetition level. The timer value of the contention resolution timer maybe selected depending on the PDSCH/PUSCH repetition level.

The contention resolution timer may be started at a first-timetransmission of the repetitive transmission of the message 3.Alternatively, the contention resolution timer may be started at a lasttime transmission of the repetitive transmission of the message 3.

The MAC layer in the MTCUE 3-1 is notified by the physical layer in theMTCUE 3-1 of the PDCCH reception. If the received PDCCH includes thetemporary C-RNTI and a corresponding contention resolution ID isincluded in the scheduled PDSCH, or if the received PDCCH includes theC-RNTI for the MTCUE 3-1 itself and the received PDCCH includes theuplink grant, the MAC layer in the MTCUE 3-1 determines a success in thecontention resolution and stops the contention resolution timer.

In the case of determining the success in the contention resolution, theMAC layer in the MTCUE 3-1 presumes a success in the random accessprocedure to flush the HARQ buffer for the message 3. In the case of thesuccess in the random access procedure, the MAC layer in the MTCUE 3-1may use the temporary PRACH repetition level as the PRACH repetitionlevel or a reference repetition level.

If the contention resolution timer expires before receiving thecontention resolution, the MAC layer in the MTCUE 3-1 determines anunsuccess in the contention resolution. In the case of determining theunsuccess in the contention resolution, the MAC layer in the MTCUE 3-1flushes the HARQ buffer for the message 3.

The preamble transmission counter is incremented by one. In a case thatthe value of the preamble transmission counter equals to the maximumnumber of transmissions of the random access preamble(preambleTransMax_r1+1) at the configured temporary PRACH repetitionlevel and the temporary PRACH repetition level is at the maximumrepetition level (RepetitionLevelMax), the MAC layer in the MTCUE 3-1notifies the higher layer (RRC layer) of a random access problem.

In the case that the value of the preamble transmission counter equalsto the maximum number of transmissions of the random access preamble(preambleTransMax_r1+1) at the configured temporary PRACH repetitionlevel and the temporary PRACH repetition level is not at the maximumrepetition level (RepetitionLevelMax), one is added to the temporaryPRACH repetition level. In other words, the temporary PRACH repetitionlevel is increased by one level. The preamble transmission counter isconfigured to one. The MAC layer in the MTCUE 3-1 performs again therandom access resource selection processing in order to retransmit therandom access preamble.

The base station device 5 performs the reception processing of themessage 3 and the transmission processing of the contention resolutionon an assumption that the MTCUE 3-1 performs the above transmissionprocessing of the message 3 and the above reception processing of thecontention resolution.

If the base station device 5 receives the message 3, the base stationdevice 5 transmits the contention resolution to the MTCUE 3-1. Therepetitive reception of the message 3 and the repetitive transmission ofthe contention resolution are performed by the number of repetitionscorresponding to the PDSCH/PUSCH repetition level indicated by thePDSCH/PUSCH repetition level command. In a case of not being notified ofthe PDSCH/PUSCH repetition level command, the base station device 5performs the message 3 reception and the contention resolutiontransmission by the number of repetitions at the repetition levelcorresponding to the random access preamble.

Reception processing on the information indicating the PDSCH/PUSCHrepetition level (PDSCH/PUSCH repetition level command) is describedbelow. The PDSCH/PUSCH repetition level is controlled (or managed) usingthe repetition level timer. While the repetition level timer is running,the PDSCH/PUSCH repetition level indicated by the PDSCH/PUSCH repetitionlevel command is valid.

The information indicating the PDSCH/PUSCH repetition level (PDSCH/PUSCHrepetition level command) is notified as the MAC control information(MAC control element) or notified as those included in the random accessresponse message. The case that the MAC layer in the MTCUE 3-1 receivesthe PDSCH/PUSCH repetition level command as the MAC control information(MAC control element) is described below.

The MAC layer in the MTCUE 3-1 configures the PDSCH/PUSCH repetitionlevel to a value of the PDSCH/PUSCH repetition level indicated by thePDSCH/PUSCH repetition level command. The MAC layer in the MTCUE 3-1notifies the physical layer in the MTCUE 3-1 of the set PDSCH/PUSCHrepetition level. The MAC layer in the MTCUE 3-1 starts or restarts therepetition level timer.

Next, the case that the MAC layer in the MTCUE 3-1 receives thePDSCH/PUSCH repetition level command through the random access responsemessage is described below.

If the transmitted random access preamble is not the random accesspreamble selected by the MAC layer in the MTCUE 3-1, in other words, ifthe random access preamble is notified through the random accessinstruction, the MAC layer in the MTCUE 3-1 configures the PDSCH/PUSCHrepetition level to a value indicated by the PDSCH/PUSCH repetitionlevel command in the random access response message. The MAC layer inthe MTCUE 3-1 notifies the physical layer in the MTCUE 3-1 of theconfigured PDSCH/PUSCH repetition level. The MAC layer in the MTCUE 3-1starts or restarts the repetition level timer.

If the repetition level timer is not running, the MAC layer in the MTCUE3-1 configures the PDSCH/PUSCH repetition level to a value indicated bythe random access response message. The MAC layer in the MTCUE 3-1notifies the physical layer in the MTCUE 3-1 of the configuredPDSCH/PUSCH repetition level. The MAC layer in the MTCUE 3-1 starts therepetition level timer.

In the case of determining an unsuccess in the contention resolution,the MAC layer in the MTCUE 3-1 may stop the repetition level timer. Ifthe repetition level timer is not running, the MAC layer in the MTCUE3-1 may configure the PDSCH/PUSCH repetition level to a default value.The default value in this case may be notified in the systeminformation. The default value may be a predefined value.

The value of the repetition level timer may be notified in the systeminformation or individually notified. A value of the transmission timingtimer may be substituted for the value of the repetition level timer.

In a case that the PDSCH/PUSCH repetition level is configured, thephysical layer in the MTCUE 3-1 performs, by the number of repetitionscorresponding to the PDSCH/PUSCH repetition level, the receptionprocessing on the physical downlink control channel (PDCCH), theenhanced physical downlink control channel (E-PDCCH) and the physicaldownlink shared channel (PDSCH), and the transmission processing on thephysical uplink control channel (PUCCH) and the physical uplink sharedchannel (PUSCH).

The base station device 5 may include, in the system information, theinformation relating to the PDSCH/PUSCH repetition level including thenumber of repetitions corresponding to the PDSCH/PUSCH repetition level,and broadcast the system information to the MTCUE 3-1. The base stationdevice 5 may notify the MTCUE individually of the information relatingto the PDSCH/PUSCH repetition level.

The information relating to the PDSCH/PUSCH repetition level may includeinformation relating to the maximum repetition level, the number ofrepetitions corresponding to the PDSCH/PUSCH repetition level, and thevalue of the repetition level timer.

The random access resource selection processing for the random accesspreamble transmission in the MAC layer in the MTCUE 3-1 is specificallydescribed with reference to FIG. 4.

First, the MAC layer in the MTCUE 3-1 determines whether no message 3 istransmitted, in other words, the MAC layer in the MTCUE 3-1 determineswhether or not the first-time random access preamble transmission (orthe initial attempt of the random access preamble transmission) isperformed (S101). If no message 3 is transmitted (in a case of Yes atS101), the MAC layer in the MTCUE 3-1 selects the PRACH repetition levelon the basis of the downlink radio channel (or the downlink path loss)(S102). The MAC layer in the MTCUE 3-1 configures the temporary PRACHrepetition level to the selected PRACH repetition level.

Then, the MAC layer in the MTCUE 3-1 configures the maximum number oftransmissions (preambleTransMax_r1) at the PRACH repetition levelcorresponding to the temporary PRACH repetition level (S103). The MAClayer in the MTCUE 3-1 selects a preamble group corresponding to thetemporary PRACH repetition level (S104).

After selecting the preamble group, the MAC layer in the MTCUE 3-1selects at random a random access preamble from the random accesspreambles in the selected preamble group (S105).

Then, the MAC layer in the MTCUE 3-1 selects a random access channel(PRACH) available for transmission (S106). The MAC layer in the MTCUE3-1 calculates a received power of the random access preamble assumed inthe base station device 5 (S107).

If the message 3 is retransmitted, in other words, in a case ofretransmission of the random access preamble (reattempt of the randomaccess preamble transmission) (in a case of No at S101), the MAC layerin the MTCUE 3-1 determines whether or not the first-time random accesspreamble transmission (or the initial attempt of the random accesspreamble transmission) at the configured temporary PRACH repetitionlevel is performed (S108).

In the case of the first-time random access preamble transmission at theconfigured temporary PRACH repetition level (in a case of Yes at S108),the MAC layer in the MTCUE 3-1 configures the maximum number oftransmissions at the PRACH repetition level corresponding to thetemporary PRACH repetition level (S109).

The MAC layer in the MTCUE 3-1 selects a preamble group corresponding tothe temporary PRACH repetition level (S110). Then, the MAC layer in theMTCUE 3-1 performs processing of selecting the random access preamble(S105), selecting the random access channel (PRACH) (S106), andcalculating the receive power of the random access preamble (107).

Not in the case of the first-time random access preamble transmission(or not in the case of the attempt of the first-time random accesspreamble transmission) at the configured temporary PRACH repetitionlevel (in a case of No at S108), the MAC layer in the MTCUE 3-1 selectsthe preamble group used for the random access preamble transmissioncorresponding to the first-time message 3 transmission (S111).

The processing on the random access response message in the MAC layer inthe MTCUE 3-1 is specifically described with reference to FIG. 5.

The MAC layer in the MTCUE 3-1 determines whether or not the randomaccess response message is received during the random access responsewindow (S201). In a case of receiving the random access response messageduring the random access response window (in a case of Yes at S201), theMAC layer in the MTCUE 3-1 determines whether or not the random accessresponse message includes a preamble ID corresponding to the transmittedrandom access preamble (S202).

If the random access response message includes the preamble ID (in acase of Yes at S202), the MAC layer in the MTCUE 3-1 determines asuccess in receiving the random access response message (S203). The MAClayer in the MTCUE 3-1 processes the transmission timing information(transmission timing command) included in the random access responsemessage transmission (S204).

Then, the MAC layer in the MTCUE 3-1 processes the informationindicating the PDSCH/PUSCH repetition level (PDSCH/PUSCH repetitionlevel command) included in the random access response message (S205).The MAC layer in the MTCUE 3-1 notifies the physical layer in the MTCUE3-1 of the uplink grant included in the random access response message(S206).

In a case of not receiving the random access response message during therandom access response window (in a case of No at S201), the MAC layerin the MTCUE 3-1 determines an unsuccess in receiving the random accessresponse message (S207). In other words, the MAC layer in the MTCUE 3-1determines a failure in receiving the random access response message.

Then, the MAC layer in the MTCUE 3-1 checks whether or not thenotification of power ramping suspension is received from the physicallayer in the MTCUE 3-1 (S208). In a case of not receiving thenotification of power ramping suspension from the physical layer in theMTCUE 3-1 (in a case of No at S208), the MAC layer in the MTCUE 3-1increments the preamble transmission counter by one (S209).

The MAC layer in the MTCUE 3-1 determines whether or not a value of thepreamble transmission counter exceeds the maximum number oftransmissions of the random access preamble at the configured temporarytemporary PRACH repetition level (S210). In a case of not receiving thenotification of power ramping suspension from the physical layer in theMTCUE 3-1 (in a case of Yes at S208), the MAC layer in the MTCUE 3-1determines the preamble transmission counter (S210). If the value of thepreamble transmission counter does not exceed the maximum number oftransmissions of the random access preamble at the configured temporaryPRACH repetition level (in a case of No at S210), the MAC layer in theMTCUE 3-1 performs the random access resource selection processingdescribed above (S215).

If the value of the preamble transmission counter exceeds the maximumnumber of transmissions of the random access preamble at the configuredtemporary PRACH repetition level (in a case of Yes at S210), the MAClayer in the MTCUE 3-1 checks whether or not the temporary PRACHrepetition level is at the maximum repetition level (RepetitionLevelMax)(S211).

If the temporary PRACH repetition level is at the maximum repetitionlevel (in a case of Yes at S211), the MAC layer in the MTCUE 3-1notifies the higher layer of a random access problem (S212). Then, theMAC layer in the MTCUE 3-1 performs the random access resource selectionprocessing described above (S215).

If the temporary PRACH repetition level is not at the maximum repetitionlevel (in a case of No at S211), the MAC layer in the MTCUE 3-1 adds oneto the temporary PRACH repetition level (S213). In other words, the MAClayer in the MTCUE 3-1 increases the temporary PRACH repetition level byone level. Then, the MAC layer in the MTCUE 3-1 configures the preambletransmission counter to one (S214). The MAC layer in the MTCUE 3-1performs the random access resource selection processing described above(S215).

The processing on the information indicating the PDSCH/PUSCH repetitionlevel (hereinafter, referred to as the PDSCH/PUSCH repetition levelcommand) in the MAC layer in the MTCUE 3-1 is specifically describedwith reference to FIG. 6.

The MAC layer in the MTCUE 3-1 determines whether or not the PDSCH/PUSCHrepetition level command is received as the MAC control information (MACcontrol element) (S301). In a case of receiving the PDSCH/PUSCHrepetition level command as the MAC control information (in a case ofYes at S301), the MAC layer in the MTCUE 3-1 configures the PDSCH/PUSCHrepetition level to a value of the PDSCH/PUSCH repetition levelindicated by the PDSCH/PUSCH repetition level command (S302).

The MAC layer in the MTCUE 3-1 notifies the physical layer in the MTCUE3-1 of the configured PDSCH/PUSCH repetition level (S303). Then, the MAClayer in the MTCUE 3-1 starts or restarts the repetition level timer(S304).

In a case of receiving the PDSCH/PUSCH repetition level command throughthe random access response message (in a case of No at S301), it ischecked whether or not the transmitted random access preamble is therandom access preamble selected by the MAC layer in the MTCUE 3-1(S305).

If the transmitted random access preamble is not the random accesspreamble selected by the MAC layer in the MTCUE 3-1 (in a case of No atS305), the MAC layer in the MTCUE 3-1 performs processing ofconfiguration the PDSCH/PUSCH repetition level (S302), notifying thePDSCH/PUSCH repetition level (S303), and starting or restarting therepetition level timer (S304).

If the transmitted random access preamble is the random access preambleselected by the MAC layer in the MTCUE 3-1 (in a case of Yes at S305),the MAC layer in the MTCUE 3-1 checks whether or not the repetitionlevel timer is running (S306).

If the repetition level timer is not running (in a case of No at S306),the MAC layer in the MTCUE 3-1 configures the PDSCH/PUSCH repetitionlevel to a value indicated by the random access response message (S307).The MAC layer in the MTCUE 3-1 notifies the physical layer in the MTCUE3-1 of the set PDSCH/PUSCH repetition level (S308). Then, the MAC layerin the MTCUE 3-1 starts the repetition level timer (S309).

If the repetition level timer is running (in a case of Yes at S306), theMAC layer in the MTCUE 3-1 ignores the PDSCH/PUSCH repetition levelcommand (PDSCH/PUSCH repetition level information) in the random accessresponse message.

The base station device 5 also uses the repetition level timer tocontrol (manage) the PDSCH/PUSCH repetition level for the MTCUE 3-1similarly to the MTCUE 3-1.

In the case that the MTCUE 3-1 receives the PDSCH/PUSCH repetition levelcommand as the MAC control information, the base station device 5 startsor restarts the repetition level timer.

In the case that the MAC layer in the MTCUE 3-1 receives the PDSCH/PUSCHrepetition level command through the random access response message andthe received random access preamble is not the random access preambleselected by the MAC layer in the MTCUE 3-1, in other words, in the casethat the random access preamble is notified by the base station device 5through the random access instruction, the base station device 5 startsor restarts the repetition level timer.

In the case that the MAC layer in the MTCUE 3-1 receives the PDSCH/PUSCHrepetition level command through the random access response message andthe repetition level timer is not running, the base station device 5starts the repetition level timer.

The case that the MTCUE 3-1 receives the PDSCH/PUSCH repetition levelcommand may be a case that the base station device 5 transmits thePDSCH/PUSCH repetition level command. The case that the MTCUE 3-1receives the PDSCH/PUSCH repetition level command may be a case that thebase station device 5 receives a positive response (ACK) from the MTCUE3-1 in response to the PDSCH/PUSCH repetition level command.

In a case that the repetition level varies during performing the randomaccess procedure, the MTCUE 3-1 may stop the random access procedure orstart again the random access procedure from the beginning. For example,the MTCUE 3-1 may measure the downlink radio quality (e.g., path loss)during performing the random access procedure, and if the PRACHrepetition level in use or the PDSCH/PUSCH repetition level is differentfrom a PRACH repetition level obtained by measuring the downlink radioquality, the MTCUE 3-1 may stop the random access procedure or use theobtained repetition level to perform again the random access procedure.

In the above description, the MTCUE may be classified depending on atype of the mobile station device. The mobile station device may beclassified into two types such that a mobile station device carrying outthe operation of the above mobile station device 1-1 may be classifiedinto a first type of mobile station device and a mobile station devicecarrying out the operation of the above MTCUE 3-1 may be classified intosecond type. The mobile station device may also be classified into twotypes such that a mobile station device carrying out the operation ofthe above mobile station device 1-1 may be classified into the firsttype of mobile station device, and the mobile station devices carryingout the operation of the above MTCUE 3-1 may be classified into secondand third types which are different in the number of repetitionsconfigured therein. The mobile station devices of the first type may beclassified into categories of a category 0 to a category 13, the mobilestation devices of the second type may be classified into a category Xother than the categories for the first type of mobile station device,and the mobile station devices of the third type may be classified intoa category Y other than the categories for the first and second types ofmobile station device.

The content described using the specific numerical value is merely anexample of a numerical value used for the sake of the description, andany suitable value may be used.

The embodiment of the present invention has been described in detailabove referring to the drawings, but the specific configuration is notlimited to the above embodiments and various amendments can be made to adesign that fall within the scope that does not depart from the gist ofthe present invention.

Furthermore, according to the embodiment, the mobile station devicesupporting machine type communication is described as one example of aterminal device or a communication device, but the present invention isnot limited to this, and can be applied to a terminal apparatus or acommunication apparatus, such as a fixed-type electronic apparatusinstalled indoors or outdoors, or a stationary-type electronicapparatus, for example, an AV apparatus, a kitchen apparatus, a cleaningor washing machine, an air-conditioning apparatus, office equipment, avending machine, and other household apparatuses.

The MTCUE 3-1 and the base station device 5 in the embodiment aredescribed using the functional block diagrams for the sake of thedescription, but the mobile station device and the base station devicemay be controlled by recording on a computer-readable recording medium aprogram for realizing the functions of the respective units in the MTCUE3-1 and base station device 5 or a part of these functions, and causinga computer system to read the program recorded on the recording mediumfor execution. The “computer system” here includes an OS and hardwarecomponents such as a peripheral device.

Furthermore, the “computer-readable recording medium” refers to aportable medium such as a flexible disk, a magneto-optical disk, a ROM,and a CD-ROM, and a storage device such as a hard disk built into thecomputer system. Moreover, the “computer-readable recording medium” mayinclude a medium that dynamically retains the program for a short periodof time, such as a communication line that is used to transmit theprogram over a network such as the Internet or over a communicationcircuit such as a telephone circuit, and a medium that retains, in thatcase, the program for a fixed period of time, such as a volatile memorywithin the computer system which functions as a server or a client.Furthermore, the program may be configured to realize some of thefunctions described above, and additionally may be configured to realizethe functions described above in combination with a program alreadyrecorded in the computer system.

The functional blocks used in each embodiment described above may berealized as an LSI that is typically an integrated circuit. Thefunctional blocks may be individually realized as chips, or may bepartially or completely integrated into a chip. The circuit integrationtechnique is not limited to LSI, and the integrated circuits for thefunctional blocks may be realized as dedicated circuits or amulti-purpose processor. Furthermore, if with advances in semiconductortechnology, a circuit integration technology with which an LSI isreplaced appears, it is also possible to use an integrated circuit basedon the technology.

The embodiments of the invention have been described in detail thus farwith reference to the drawings, but the specific configuration is notlimited to the embodiments. Other designs and the like that do notdepart from the essential spirit of the invention also fall within thescope of the patent claims. In other words, this specification of thepresent application is described for the purpose of illustration, andputs no limitation on the embodiments of the present invention.

As some aspects in the present invention, the following measures may betaken.

(1) A radio communication system according to an aspect of the presentinvention is a radio communication system in which a base station deviceand a terminal device are configured to communicate with each other and,the terminal device is configured to perform a random access procedure,in which the base station device is configured to notify the terminaldevice of random access common configuration information including themaximum number of transmissions corresponding to a repetition level foreach repetition level, and a MAC layer in the terminal device isconfigured to notify an RRC layer in the terminal device of a randomaccess problem in a case that a first counter exceeds the maximum numberof transmissions corresponding to the repetition level and therepetition level is at the maximum repetition level, and the RRC layerin the terminal device is configured to perform connectionre-establishment processing in a case that the RRC layer is notified ofthe random access problem by the MAC layer in the terminal device.

(2) In the radio communication system according the above aspect of thepresent invention, the MAC layer in the terminal device has a firstcounter incremented at least in a case that an unsuccess in receivingthe random access response is considered and a notification of powerramping suspension is not received from the physical layer in theterminal device.

(3) A terminal device according to an aspect of the present invention isa terminal device configured to communicate with a base station deviceand perform a random access procedure, in which, a MAC layer in theterminal device is configured to notify an RRC layer in the terminaldevice of a random access problem in a case that a first counter exceedsthe maximum number of transmissions corresponding to a repetition leveland the repetition level is at the maximum repetition level.

(4) The MAC layer in the terminal device according the above aspect ofthe present invention is further configured to increase the repetitionlevel in a case that the first counter exceeds the maximum number oftransmissions corresponding to the repetition level and the repetitionlevel is not at the maximum repetition level.

(5) The MAC layer in the terminal device according the above aspect ofthe present invention is further configured to increment the firstcounter at least in a case that an unsuccess in receiving the randomaccess response is considered and a notification of power rampingsuspension is not received from a physical layer in the terminal device.

(6) A base station device according to an aspect of the presentinvention is a base station device configured to communicate with aterminal device, and the base station device is configured to notify theterminal device of random access common configuration informationincluding the maximum number of transmissions corresponding to arepetition level for each repetition level, and assume that therepetition level for the terminal device varies depending on the maximumnumber of transmissions corresponding to the repetition level, and asuccess or failure in receiving a random access response by the terminaldevice.

(7) A radio communication method according to an aspect of the presentinvention is a radio communication method applied to a terminal device,the terminal device is configured to communicate with a base stationdevice and perform a random access procedure, the method including thesteps of notifying a higher layer of a random access problem in a casethat a first counter exceeds the maximum number of transmissionscorresponding to a repetition level and the repetition level is at themaximum repetition level, and increasing the repetition level in a casethat the first counter exceeds the maximum number of transmissionscorresponding to the repetition level and the repetition level is not atthe maximum repetition level.

(8) The radio communication method according the above aspect of thepresent invention further includes the step of incrementing the firstcounter at least in a case that an unsuccess in receiving the randomaccess response is considered and a notification of power rampingsuspension is not received from a lower layer.

(9) An integrated circuit according to an aspect of the presentinvention is an integrated circuit applied to a terminal device, theterminal device being configured to communicate with a base stationdevice and perform a random access procedure, the integrated circuitincluding a first unit configured to notify a higher layer of a randomaccess problem in a case that a first counter exceeds the maximum numberof transmissions corresponding to a repetition level and the repetitionlevel is at the maximum repetition level, and a second unit configuredto increase the repetition level in a case that the first counterexceeds the maximum number of transmissions corresponding to therepetition level and the repetition level is not at the maximumrepetition level.

(10) The integrated circuit according the above aspect of the presentinvention further includes a third unit configured to increment thefirst counter at least in a case that an unsuccess in receiving therandom access response is considered and a notification of power rampingsuspension is not received from a lower layer.

The present invention can be applied to at least mobile phones, personalcomputers, tablet-type computers, and the like.

REFERENCE SIGNS LIST

-   1-1 to 1-3 Mobile station device-   3-1 to 3-3 MTCUE-   5 Base station device-   101, 201 Data generation unit-   103, 203 Transmission data storage unit-   105, 205 Transmission HARQ processing unit-   107, 207 Transmission processing unit-   109, 209 Radio unit-   111, 211 Reception processing unit-   113, 213 Reception HARQ processing unit-   115, 215 MAC information extraction unit-   117, 217 PHY control unit-   119, 219 MAC control unit-   121, 221 Data processing unit-   123, 223 RRC control unit

The invention claimed is:
 1. A radio communication system in which abase station device and a terminal device are configured to communicatewith each other and the terminal device is configured to perform arandom access procedure, wherein: the base station device includes: afirst processor; and a first memory in electronic communication with thefirst processor, the first memory storing instructions executable by thefirst processor to notify the terminal device of random accessinformation including: (i) information for selecting a level fordetermining a repetition number, (ii) a first number and a last numberof preambles included in a group corresponding to the level, and (iii) anumber of attempts of preamble transmission configured for each level;and the terminal device includes: a second processor; and a secondmemory in electronic communication with the second processor, the secondmemory storing instructions that are executable by the second processorto: select, in a MAC layer, the level based on a received downlink radioquality, and perform, in the MAC layer, processing of increasing thelevel in a case that a first counter exceeds a maximum of the number ofattempts of transmission, the maximum being configured for the level. 2.A terminal device configured to communicate with a base station deviceand perform a random access procedure, wherein: the terminal deviceincludes: a processor; and a memory in electronic communication with theprocessor, the memory storing instructions executable by the processorto: receive, from the base station device, random access informationincluding: (i) information for selecting a level for determining arepetition number, (ii) a first number and a last number of preamblesincluded in a group corresponding to the level, and (iii) a number ofattempts of preamble transmission configured for each level, select, ina MAC layer, the level based on a received downlink radio quality, andperform, in the MAC layer, processing of increasing the level in a casethat a first counter exceeds a maximum of the number of attempts oftransmission, the maximum being configured for the level.
 3. A basestation device configured to communicate with a terminal device,wherein: the base station device includes: a processor; and a memory inelectronic communication with the processor, the memory storinginstructions executable by the processor to: notify the terminal deviceof random access information including: (i) information for selecting alevel for determining a repetition number, (ii) a first number and alast number of preambles included in a group corresponding to the level,and (iii) a number of attempts of preamble transmission configured foreach level.
 4. A radio communication method applied to a terminal deviceconfigured to communicate with a base station device and perform arandom access procedure, the radio communication method comprising thesteps of: receiving, from the base station device, random accessinformation including: (i) information for selecting a level fordetermining a repetition number, (ii) a first number and a last numberof preambles included in a group corresponding to the level, and (iii) anumber of attempts of preamble transmission configured for each level;selecting the level based on a received downlink radio quality; andincreasing the level by a MAC layer in the terminal device in a casethat a first counter exceeds a maximum of the number of attempts oftransmission, the maximum being configured for the level.
 5. A radiocommunication method applied to a base station device configured tocommunicate with a terminal device, the radio communication methodcomprising: notifying, by the base station device, the terminal deviceof random access information including: (i) information for selecting alevel for determining a repetition number, (ii) a first number and aEast number of preambles included in a group corresponding to the level,and (iii) a number of attempts of preamble transmission configured foreach level.
 6. The radio communication system according to claim 1,wherein: the random access information further includes informationindicating a relationship between the level and a timer value of acontention resolution timer, and the second memory further stores aninstruction that is executable by the second processor to select, in theMAC layer, the timer value of the contention resolution timercorresponding to the selected level.
 7. The terminal device according toclaim 2, wherein: the random access information further includesinformation indicating a relationship between the level and a timervalue of a contention resolution timer, and the memory further stores aninstruction that is executable by the processor further to select, inthe MAC layer, the timer value of the contention resolution timercorresponding to the selected level.
 8. The base station deviceaccording to claim 3, wherein: the random access information furtherincludes information indicating a relationship between the level and atimer value of a contention resolution timer.
 9. The radio communicationmethod according to claim 4, wherein: the random access informationfurther includes information indicating a relationship between the leveland a timer value of a contention resolution timer, and the radiocommunication method further comprises the step of selecting the timervalue of the contention resolution timer corresponding to the selectedlevel.
 10. The radio communication method according to claim 5, wherein:the random access information further includes information indicating arelationship between the level and a timer value of a contentionresolution timer.